Characteristics of tree-ring density at different stem heights and their climatic responses.

Taking windfall woods of Picea schrenkiana in the southern mountainous area of the Ili Prefecture as the research object, tree-ring density chronologies were developed from the discs for maximum density (MXD), minimum density (MID), mean earlywood density (EWD), and mean latewood density (LWD) at five different stem heights (1.3, 5, 10, 15 and 20 m) to examine the climatic responses of tree-ring density by correlation analysis with local meteorological data. The results showed that there was a good coherence among the four types of tree-ring density chronologies for the same stem height, which was relatively significant for the data from 10, 15 and 20 m. The LWD had good coherence among different stem heights, while the climatic responses of tree-ring density at different stem heights varied. The MXD and LWD at 15 m were sensitive to mean tempera-ture from July to September in the previous year and from May to September in the current year. It might underestimate the response of P. schrenkiana to temperature if we sample tree-ring at 1.3 m.